one-forty-ninth part of that of the terrestrial spheroid– not
one of her secrets was able to escape the eyes of the
astronomers; and these skillful men of science carried to an
even greater degree their prodigious observations.
Thus they remarked that, during full moon, the disc appeared
scored in certain parts with white lines; and, during the
phases, with black. On prosecuting the study of these with
still greater precision, they succeeded in obtaining an exact
account of the nature of these lines. They were long and narrow
furrows sunk between parallel ridges, bordering generally upon
the edges of the craters. Their length varied between ten and 100
miles, and their width was about 1,600 yards. Astronomers called
them chasms, but they could not get any further. Whether these
chasms were the dried-up beds of ancient rivers or not they were
unable thoroughly to ascertain.
The Americans, among others, hoped one day or other to
determine this geological question. They also undertook to
examine the true nature of that system of parallel ramparts
discovered on the moon’s surface by Gruithuysen, a learned
professor of Munich, who considered them to be “a system of
fortifications thrown up by the Selenitic engineers.” These two
points, yet obscure, as well as others, no doubt, could not be
definitely settled except by direct communication with the moon.
Regarding the degree of intensity of its light, there was
nothing more to learn on this point. It was known that it is
300,000 times weaker than that of the sun, and that its heat has
no appreciable effect upon the thermometer. As to the
phenomenon known as the “ashy light,” it is explained naturally
by the effect of the transmission of the solar rays from the
earth to the moon, which give the appearance of completeness to
the lunar disc, while it presents itself under the crescent form
during its first and last phases.
Such was the state of knowledge acquired regarding the earth’s
satellite, which the Gun Club undertook to perfect in all its
aspects, cosmographic, geological, political, and moral.
CHAPTER VI
PERMISSIVE LIMITS OF IGNORANCE AND BELIEF IN THE UNITED STATES
The immediate result of Barbicane’s proposition was to place upon
the orders of the day all the astronomical facts relative to the
Queen of the Night. Everybody set to work to study assiduously.
One would have thought that the moon had just appeared for the
first time, and that no one had ever before caught a glimpse of
her in the heavens. The papers revived all the old anecdotes in
which the “sun of the wolves” played a part; they recalled the
influences which the ignorance of past ages ascribed to her; in
short, all America was seized with selenomania, or had become moon-mad.
The scientific journals, for their part, dealt more especially with
the questions which touched upon the enterprise of the Gun Club.
The letter of the Observatory of Cambridge was published by them,
and commented upon with unreserved approval.
Until that time most people had been ignorant of the mode in which
the distance which separates the moon from the earth is calculated.
They took advantage of this fact to explain to them that this
distance was obtained by measuring the parallax of the moon.
The term parallax proving “caviare to the general,” they further
explained that it meant the angle formed by the inclination of two
straight lines drawn from either extremity of the earth’s radius
to the moon. On doubts being expressed as to the correctness of
this method, they immediately proved that not only was the mean
distance 234,347 miles, but that astronomers could not possibly
be in error in their estimate by more than seventy miles either way.
To those who were not familiar with the motions of the moon,
they demonstrated that she possesses two distinct motions, the
first being that of rotation upon her axis, the second being
that of revolution round the earth, accomplishing both together
in an equal period of time, that is to say, in twenty-seven and
one-third days.
The motion of rotation is that which produces day and night on
the surface of the moon; save that there is only one day and one